Mean-pressure indicator or power-gage



Patented July 26, I898. G. F. ATWOOD.

MEAN PRESSURE INDICATOR 0R PowER GAGE.

(Application filed Mar. 9, 1897.)

3 Sheets-Sheet I.

(No Model.)

THE Noams PETERS co, PHUTOUTHO" wnsHlNoToN, n. c.

No. 607,8!9. Patented July 26, I898. G. F. ATWOOD.

MEAN PRESSURE INDICATOR UR POWER GAGE.

' (Application filed Mar. 9, 1897.) (No Model.) 3 Sheets-Sheet 2.

INVENTOR:

WITNESSES: a/ a, t M /5 By 111's Zkorney @mmA-W THE Noam PEYERS co. PNOTOJJTHO. WASHINGTON, 0. c.

N0. 607,8l9. Patented July 26, I398. G. F. ATWOUD. MEAN PRESSURE INDICATOR 0R POWER GAGE.

(Application filed Mar. 9, 1897.,

3 Sheets-Sheet 3.

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INVENTOR:

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GEORGE F. ATlVOOD, OF ORANGE, NEW' JERSEY, ASSIGNOR OF ONE-HALF TO FREDERICK M. HOYT, OF STAMFORD, CONNECTICUT.

MEAN-PRESSURE INDICATOR OR POWER -GAGE.

SPECIFIGATIONforming part of Letters Paltent No. 607,819, dated July 26, 18 98.

Application filed March 9, 1397.

To all whom it may 001mm:

Be it known that I, GEORGE F. Arwoon, a citizen of the United States, residing at Orange, in the county of Essex and State of New Jersey, have made a new and useful Invention in the Nature of a Mean-Pressure Indicator or Power-Gage, of which the follow ing is a specification. I

My invention is designed to give continuQ ous measurements by visual indications .of the amount of energy given to prime moverssucl1 as steam, gas, air, and water motors-and in such manner that the indications will be of a dead-beat naturethat is to say, will give indications of varying loads put upon the prime mover without sudden or violent fluctuations.

To this end my invention consists in a novel apparatus for accomplishing this result, and the especial points of novelty thereof will be particularly pointed out in the claims at the end of the following specification, reference being had to the accompanying drawings for a full understanding of the invention, in which Figure 1 is a vertical sectional view of the entire apparatus, taken on the lines 1 1, Fig.

3, and 1 1, Fig. 4, and as seen looking at those figures in the direction of the arrows from the bottom toward the top of the drawings. Fig. 2 is a plan view as seen looking at Fig 1 from the bottom toward the top of the draw-- ings, part of the protecting or inclosing casing of the propelling turbine or motorbeing broken away for the better illustration of the interior structure thereof. Fig. 3 is a plan view of the instrument as seen looking at Fig. 1 from the top toward the bottom of the draw ings, said figure illustrating the dial and the, dial or indicating hand in zero position in" full lines and in operative position in dotted lines, together with a view of the retarding-' spring attached to the shaft for retarding the forward movement of the dial-hand. Fig. 4 is a horizontal sectional view taken on the broken sectional line 4 at, Fig. '1, and as seen looking in the direction of the arrows upon that figure from the top toward the bottom of' the drawings. Fig. 5 is a sectional View, 50 taken through the body of the turbine or prosemi No. 626,595. (No model.)

pellingmotor and its adjacent parts, illustrating the manner of connecting the steampipes to the jet-pipes through which the steam flows to the motor, the propelling-fan connected thereto being shown in elevational 5 5 view Fig. 6 is a sectional view of the cylinder of a well-known form of steam-engine, illustrating the manner of connecting my steani-dynamometer thereto and its mode of operation in connection therewith.

Prior to my invention it was customary in obtaining the horse-power of steam-engines or analogous prime movers to utilize a steamindicator the motive part of which was actuated by the steam as it entered the cylinder at one end thereof and caused to trace a diagram upon a card during one or two strokes of the engine or motive device. This diagram was then used as the basis of a computation of the amount of energy given to the piston during the particular interval occupied in its construction. The calculations were usually made by tracing the diagram or card by a planimeter in order to obtain the area thereof, and then by a well-known formula the mean effective pressure and total energy were calculated. This diagram or card, as it is termed, is always traced upon a reduced scale, audit is obvious, therefore, that any error in the measurement of its area or average height which represents the mean pressure will be multiplied in a ratio corresponding to "the reduction of the scale upon which the card is constructed. It is well known, furthermore, that these computations involve v considerable time and are at best only momentary indications of the actual energy used. It is very desirable, therefore, to devise an instrument which will at all times indicate upon visual inspection the actual energy given to the'piston without the necessity of performing laborious calculations, and it was with'this end in view that the present "invention wasconceived and devised.

V The well-known formula forv calculating 5 the: energy of an engine contemplates the multiplying the area of the-piston hea'dfin square inches by the mean effective pressure and the multiplication of this product by the distance traveled in feet per minute, which total product is divided by thirty-three thousand foot-pounds. The area of the pistonhead and thirty-three thousand foot-pounds being constant the quantities to be measured are therefore the mean effective pressure and the velocity in feet per minute. The latter is easily obtained by measuring the revolutions per minute of the shaft of the engine and multiplying the same by twice the length of the stroke in feet; but, as above explained, the measurement of the mean effective pres sure involves the described method of tracing a diagram with an indicator.

In all self-governing engines the speed is practically constant, and an instrument that will measure and indicate the mean effective pressure can be calibrated so as to read in units of horse-power, inasmuch as the quantities are constant, with the exception of that which is to be measured, and it will vary in proportion to the total energy or horsepower. The above holds true, however, only when the conditions are as ordinarily found with existing self-governed steam-engines and a properly-constructed indicating instrument. My invention comprehends such an instrument and is adapted to be attached to either or both ends of the cylinder of well-known forms of steam-engines, and in practice I use a small turbine or rotary motor actuated by one or more jets of steam or water directed through a jet pipe or nozzle and impinging upon the blades or buckets thereof at its periphery or sides. The shaft of this turbine or rotary motor is connected mechanically to a dynamometer which will balance or measure the force given by the jet or jets of steam or water, and the scale of the dynamometer may be either graduated arbitrarily and the reading multiplied by a constant, or it may be calibrated empirically from actual tests, thus indicating the desiredunits of energy-such, for instance, as mean effective pressure or horse-power.

Referring now to the drawings in detail, in all of which like letters of reference represent like parts wherever used, A represents a metallic cylindrical inclosin g casin g secured by screws to a a to a cylindrical motor-chamber B, which in turn is secured to a base or support B by screws nu 91; extending upward into a rim V, said parts when united together constituting a steam-tight chamber for a rd tary turbine or motor T of disk form, having its undersurface provided with radial grooves or buckets g g and surrounded in turn by a metallic band or rim r, said motor being secured by a drum or shaft 8, provided with ball-bearings b b at its opposite ends and adapted to rotate upon said bearings around a shaft S, supported bya stationary shaft S, extending downward in a hub or extension R in the bottom of the part B.

t t are steam or water jet pipes secured in the upper ends of the steam-tight collars K K and located at such angles that the steam emitted therefrom will give to the rotary turbine or motor T rotation in the direction of the arrow, Fig. 2.

F is a rotary fan having 'two or more blades or vanes secured to the hollow shaft S and adapted to rotate therewith in a chamber above the steam-chamber B. F is a similar rotary fan carried by a shaft 3 provided with a delicate jewel-bearing j in the upper end of the shaft S and a second delicate jewel-bearingj in a set-screw .9, supported by the free end of an arm E secured by screws e e to the top of an instrument and above a dial-plate D, calibrated, as shown, and sustained by posts or pillars p p.

G is a glass cover inclosing the dial D and dial-hand H, said cover being secured to the inclosing casing A by a ring or rim R and screws 0 0.

D is a Foucault disk, of copper or other diamagnetic material, sustained by the shaft 8 and adapted to rotate between the poles of a number of permanent magnets M M M, its function being to steady the dial-hand H from violent fluctuations upon sudden changes of speed of the turbine or motor T and give to ita dead-beat action.

sis a delicate spiral retractile spring secured at one end to the shaft 5 and at the other to the body or frame of the instrument.

P and P are pipes for admitting a motive agent, such as steam or water, to the j et-pipes t 25, said pipes being secured at opposite ends of the cylinder, as shown in Fig. 6, and connected to the steam-tight collars K K by screw-threaded collars Q, having frictional bearing upon rims or beads 7.7, m 777. being steam tight packing rings of well known form. The steam-tight collars K K are secured to the base 13 of the steam-chamber B by set-n uts N N, clamping said collars thereto through the agency of beads or rims L L.

E is an exhaust-pipe for permitting of the exhaust of the motive agent-such as steam, air, gas, or water-after it has passed through the instrument, said exhaust-pipe being secured to the steam-chamber B by screwthreads, as clearly indicated at E in Fig. 2, and connected directly with the main exhaustpipe of the engine proper, so that the conditions of exhaust for the instrument are similar to those of the engine.

E is an extension or lug on the lower part of the base B of the steam-chamber B, and NV is a screw-bolt provided with a milled head and a set-nut J, its function being to bear let for the steam or motive agent is provided from the cylinder of the engine or prime mover through the motor of a mean-pressure indicator to the exhaust of the prime mover or its equivalent, so that I thereby utilize or absorb a portion of the steam or motive agent which is given to the cylinder of the prime mover or engine to drive such a motor hav ing a sufficient moment of inertia to enable it to run at a practically constant velocity for successive impulses of equal values in pressures and duration, which motor in turn drives indicating mechanism adapted to indicate directly in established units the power or pressure utilized to drive the prime mover or engine, and this is accomplished by causing the steam which successively enters the cylinder at opposite ends behind the piston to continuously drive a rotary motor having a definite moment of inertia and adapted to perform a definite amount of work proportional tothe work performed by the prime mover or engine the power of which it is desired to ascertain, and in the application of this generic principle of measuring a definite proportion of power used and giving a direct visual indication of the same lies the essence of my invention.

In constructing my improved apparatus it will be understood that the dials are calibrated for engines of known horse-power and the spiral retractile springs s therefor are of a known retractile capacity, so that when an apparatus is constructed for a given engine of, say, one hundred horse-power and properly adjusted it will give correct readings during the usage of the same for all intermediate powers. Although I preferably connect my indicator to both ends of the cylinder by steam-pipes P P, so as to give the same impulsive eifect upon the indicating-motor as is had upon the piston proper of the engine, it is obvious that it might be connected at either end thereof at will; but by connecting to both ends I obtain more accurate results.

My improved apparatus for indicating horse-power is operated as follows: The dynamometer is connected by steam-pipes P P to the opposite ends of the cylinder 0, as shown in Fig. 6, and the engine set in operation in the usual way, a well-known form of valve mechanism therefor being shown at the lower part of that figure. As the steam is admitted to one end of the cylindersay the righta definite proportion of it passes through the steam-pipe I and collar K to the jet-pipe t, andin passing therefrom acts in a wellknown manner upon the grooves or buckets g of the turbine or rotary motor T, tending to set the same in motion. IVhen the piston reaches its extreme stroke on the left, steam now enters through the pipe P and collar K and jetpipe 25, acting in the same manner upon the turbine T, the exhaust-steam passing out of the chamber B by the exhaust-pipe E. This successive impulsive action sets the turbine or rotary motor in operation and imparts thereby continuous rotary movement to the propelling-fan F in such manner as to set in circulation in a given direction the volume of air within the chamber, which in turn acts upon the blades of the fan F, thus causing it to tend to rotate against the stress of the spiral spring s and dampening effect of the magnets M upon the diamagnetic Foucault disk D. As the engine speeds up the dialhand II continues to move to the right until the actual energy absorbed is indicated on the dial. Any sudden increase upon the demands of the engine is of course followed by a corresponding infioW of steam into the cylinder, and consequently by a proportional flow of such steam to the rotary turbine or motor T, thus ultimately indicating directly upon the dial the proportionate change.

It will be apparent that the Foucault disk D, the retractile spring 8, and fan F are of such nature as to act when in operation with a retarding action upon the speed of the propelling-fan F, and consequently the motor cated by a gradual increasing or decreasing movement of the dial-hand II either to the right or the left, dependent upon an increase or decrease of the energy absorbed, as the case may be. 4

Although I have disclosed herein a specialform of apparatus for indicating directly the actual energy of an engine, I do not limit myself to the particular mechanism shown and described, as I believe that I am broadly entitled to claim a mean-pressure indicator pro- In short, I believe my invention to be of such scope as to entitle me to claim generically a mean-pressure indicator which gives direct readings of the effective pressure given to the engine to which it is attached.

Having thus described my invention, what I claim, and desire to secure by Letters Patent of the United States, is

1. A mean-pressure indicator or power-gage meter for steam, or analogous engines, consisting of a continuously-driven motor actuated directly by a part of the steam which drives the engine and having sufficient momentum to make its velocity substantially constant for successive impulse effects of the steam when of equal value, and an indicator driven by the motor and adapted to give visual indications of a unitary nature, substantially as described.

2. A mean-pressure indicator or power-gage consisting of a turbine motor having sufficient momentum to continue its movement during the interval between successive. impulses of the moving agent, said motor being attached to a rotary fan, in combination with a second fan adapted to be propelled by the first-named fan and an indicating-hand carried by a shaft which sustains the second fan; means as a retractile spring for retarding or opposing the forward movement of said fan, together with a dial calibrated to read units of measurement, substantially as described.

3. A mean-pressureindicator or power-gage meter for steam or analogous engines consisting of a rotary motor actuated directly by a part of the motive agent which drives the engine and having a sufficient moment of inertia to render its velocity a measure of the mean pressure of the successive impulses of such motive agent, in combination with an indicator driven by the motor and adapted to give visual indications of a unitary nature, such as horse-power, substantially as described.

4. A mean-pressure indicator or power-gage meter consisting of a turbine motor having a sufficient moment of inertia to continue its movement in the same direction between successive impulses of the motive agent, such as steam, in combination with one or more jetpipes adapted to convey a part of the motive agent directly from the cylinder of the engine to and through the turbine motor at the same time that it is applied to the piston-head of the engine together with means for indicating definite units of energy attached directly to the movable part of said turbine motor, substantially as described.

5. Amean-pressure indicator orpower-gage consisting of a movable motive device in the nature of a'rotary turbine, said motive device having sufficient moment of inertia to continue its movement during successive applications of the motive agent, such as steam; one or more jetpipes operatively connected with the engine the horse-power of which it is desired to ascertain, said jet-pipe or jetpipes being so connected to the engine as to receive the steam therefrom at the same time that it is utilized by the engine, in combination with indicating mechanism driven by said rotary turbine, and opposing means in the nature of a retractile spring together with steadying means, all of said parts acting substantially as and for the purpose described.

6. Amean-pressure indicator orpower-gage meter for steam or analogous prime movers or engines,consisting of a continuously-driven turbine constructed to have a sufficient moment of inertia to continue its movement during successive impulses and provided with one or more jet-pipes adapted to deliver steam upon the buckets of the motor; means for varying the angular location of said jet-pipes so as to adjust the instrument to the prime mover with which it is to be moved, in combination with an indicator driven by the motor, substantially as described.

In testimony whereof I have hereunto subscribed my name this 8th day of March, 1897.

GEORGE F. ATWOOD. Witnesses:

O. J. KINTNER, M. M. ROBINSON. 

